The present invention relates to a light system for medical photodynamic applications.
The term “medical photodynamic applications” as used herein refers to photodynamic diagnosis and/or therapy of the human or animal body.
Light systems of this kind are known and are being developed, for example, by the Applicant under the name T-light. Such a light system is described, for example, in W. Beyer, R. Waidelich, R. Knuechel, H. Stepp, R. Baumgartner, A. Hofstetter: Technical concepts for white light photodynamic therapy of bladder cancer. Med. Laser Appl. 17:3740 (2002).
Such light systems are used in photodynamic therapy, for example. In this treatment method, substances called photosensitizers are administered to a patient. These photosensitizers can either be applied specifically to malignant tissue or are more preferably compounds which, by their nature, collect in malignant tissue. When these photosensitizers are irradiated with light of specific wavelengths, a phototoxic effect takes place which can destroy the tissue in which the photosensitizers have collected.
In order to achieve a maximum effect of the treatment, the greatest possible amount of light has to be applied to the tissue treated with the photosensitizer.
In the case of bladder cancer, this is done, for example, using special catheters which comprise a light guide at whose distal end a scattering rod is arranged so that the light introduced into the light guide at the proximal end is distributed across the greatest possible area. To ensure that such light guides can be sterilized and do not lead to a transmission of diseases between patients, they are generally connected to the light source in a detachable manner via a plug.
It has now been found that upon detachment and fitting of the plug into a plug socket of the light system, this plug socket has to be readjusted in order to position the entrance interface of the light guide in the focus of the light source, so as to introduce the greatest possible amount of light into the light guide.
In the previously known systems, this is done by a reference fiber being placed in the plug socket, and the plug socket then being manually adjusted. This reference fiber is then removed from the plug socket and replaced by the proximal end of the light guide. This is an extremely complicated and time-consuming process which considerably reduces the period of time during which such a system is available for patient treatment. Moreover, the adjustment of such a system requires specialized personnel, which considerably increases the costs involved in using this system.
It is therefore an object of the invention to describe a light system in which the adjustment of the position of the entrance interface of the light guide and of the light source relative to one another can be achieved much more easily and quickly, while at the same time ensuring that the greatest possible amount of light is transmitted to the application site.